In the completion of oil wells, in one type of process a tubular well tool assembly is run into the wellbore above a production liner and a liner hanger. The liner hanger is adapted to be seated in the wellbore and cemented in place. The tubular well tool assembly above the liner hanger is adapted to receive a retrievable tubular receptacle. Either the receptacle or the well tool assembly is arranged with a polished bore to sealing and slideably receive a tubular assembly. The sliding and sealing relationship of the tubular member permits an attached tubing string to lengthen or shorten due to environmental effects in the well bore during operation of the well. Thus, the polished bore sliding seal between the tubing string and downhole equipment permits the tubing string to shift under different temperatures and pressures.
One of the difficulties that occurs with use of this kind of equipment is that there is an open annulus between the sliding seal and the upper end of the tubular well tool assembly where solids from oil well drilling fluids may precipitate out and tend to clog up the assembly.
The present invention is intended to eliminate the precipitation of solids in the annulus between a tubing string and the upper end of a tubular well tool assembly. In the present invention, the tubular well tool assembly is provided with a releasable latching device to cooperate with a latching groove in the upper end of the tubular well tool assembly to provide a removable barrier which prevents precipitation of solids from the wellbore into the annulus between the tubing and the tubular well tool assembly.